The following information is from our Grape Growers Guide:
Table Grape Varieties
Successful table grape cultivation in Colorado requires optimum cultural practices; but, with certain considerations, they can be grown with the same management skills as wine grapes. The intent of this section in the Colorado Grape Grower’s Guide is to provide the grower with additional information for table grapes that has not been addressed previously in the text.
Varietal selection is extremely important and involves considerations of winter hardiness and marketability. Information concerning performance of specific cultivars in Colorado is limited although some information does exist. A summary of vegetative growth and fruit characteristics for 15 of the most popular seedless table grape cultivars that are currently available is provided in Tables 7 and 8. The following descriptions are of several varieties grown at Orchard Mesa Research Center that appear well suited for the wine grape growing regions of Colorado.
Himrod: This white variety is a cross between Ontario X Sultanina (Thompson Seedless) and has excellent quality fruit which is juicy and sweet with pleasant flavor. This vigorous vine is moderately hardy; it survived the 1989 freeze of -22oF with little trunk damage. Himrod tends to shed individual berries when picked; this should be considered before planting large acreages.
Interlaken: A second white variety that is also a cross between Ontario X Sultanina. This vigorous vine bears heavy crops early in the season, has good flavor and is somewhat less hardy than Himrod.
Lakemont: A third white variety of the same parentage as Interlaken (Ontario X Sultanina). It produces large compact clusters with quality that approaches that of Himrod and ripens a week or two later. It has moderate to low winter hardiness.
Suffolk Red: A large-berried, red seedless grape with good quality. It has low winter hardiness and sets loose clusters. It survived the eight winters prior to 1989, but was winter killed to ground level by the -22oF temperatures during January of 1989.
Other seedless varieties (e.g., Concord Seedless, Thompson Seedless, Flame Seedless) have been tested at OMRC. However, their performance has been poor and they cannot be recommended for commercial production. There are many seeded varieties (e.g., Concord, Niagra, Steuben, Golden Muscat, etc.) that can be successfully cultivated in Colorado; all have more intense marketing challenges when competing with the more desirable seedless varieties. Pruning and improving grape quality are two additional areas that should be modified from wine grape production. Pruning and training table grapes depends on variety and the overall objective of the operation. Pruning and training table grapes can be identical to that of wine grapes, but often should be modified to help equalize production for large average crops of high-quality fruit. Most varieties mentioned above are vigorous and should be trained to a pruning system that allows for that vigor such as the Geneva Double Curtain, Four Arm Kniffen and/or Umbrella Kniffen. These systems require more trellis expense but may be better suited for the more vigorous varieties.
Quality of table grapes can be improved by blossom thinning (i.e., removal of flower clusters before bloom and of immature clusters), a cultural practice not typically performed on wine grapes. Like pruning, thinning concentrates the activities of the vine into the remaining parts and strengthens the vine by limiting the crop without diminishing the leaf area. Girdling, also called ringing, is an old practice that improves set, increases size of berries and advances maturation; it should NOT be performed in Colorado due to the increased risk of Crown Gall infection.
Table 7. Vegetative growth characteristics of seedless table grape cultivars.
Ripening Vine Yields/ Winter
Variety Season Vigor Vine Hardiness
Canadice Early Medium High High
ChallengerMid Season Medium Medium Medium
Late Mid Medium Low High
Glenora Mid Season Medium Low Low
Himrod Early Medium Low Medium
Interlaken Very Early Medium Medium Low
Lakemont Mid Season High High Low
Mars Early Medium Medium Medium
Mid Season Medium High Medium
Reliance Early High Medium High
Remaily Late – Mid Medium High Low
Romulus Late Medium Medium Medium
Mid Season High Low Low
Vanessa Mid Season Medium Medium High
Venus Very Early High High Medium
Table 8. Fruit characteristics of seedless table grape cultivars. __________________________________________________
Berry Cluster Cluster
Variety Color Flavor Size Size Compactness
Canadice Red Good Medium Medium Tight
Challenger Red Good Large Medium Loose
Blue Fair Small Small Loose
Glenora Blue Good Medium Medium Compact
Himrod White Excellent Medium Medium Loose
Interlaken White Good Medium Medium Compact
Lakemont White Good Medium Large Compact
Mars Red Good Medium Small Compact
Red Excellent Medium Medium Compact
Reliance Red Good Medium Medium Loose
Remaily WhiteFair Large Large Compact
Romulus White Fair Small Large Compact
Red Excellent Large Medium Loose
Vanessa Red Good Medium Medium Compact
Venus Blue Good Large Large Tight